Hald Jan, Petersen Jan C, Henningsen Jes
Danish Fundamental Metrology Ltd., Matematiktorvet 307, DK-2800 Kgs. Lyngby, Denmark.
Phys Rev Lett. 2007 May 25;98(21):213902. doi: 10.1103/PhysRevLett.98.213902.
We report on saturated absorption in a hollow-core photonic band-gap fiber filled with 12C2H2 molecules. We find that slow molecules provide a major contribution to the signal in the limit of low optical power and low pressure where the signal deviates significantly from the usual Lorentzian line shape. In particular, we observe a linewidth reduction of about 3 times as compared to the transit-time limited linewidth.
